(a) Technical Field
The present invention relates to a liquid crystal display.
(b) Related Art
In general, liquid crystal displays include two display panels having pixel electrodes and a common electrode, and a liquid crystal layer having an anisotropic dielectric interposed therebetween. The pixel electrodes are arranged in a matrix and connected to switching devices such as thin film transistors (TFTs) to sequentially receive data voltages by rows. The common electrode is disposed over the entire surface of the display panel and applied with a common voltage. The pixel electrode, the common electrode, and the liquid crystal layer interposed therebetween constitute a liquid crystal capacitor. The liquid crystal capacitor together with the switching element connected thereto form a pixel.
Liquid crystal displays may be used to display images by applying an electric field to a liquid crystal layer between the two display panels and adjusting the transmittance of light passing through the liquid crystal layer by controlling the electric field strength. If a one-directional electric field is applied to the liquid crystal layer for a long period of time, degradation of the liquid crystal display may occur. In order to prevent such degradation, the polarities of the data voltages with respect to the common voltage may be inverted for each frame, pixel row, or pixel.
However, in the case of row inversion, the range of data voltages that may be used for image display is small in comparison with the range of data voltages that may be used for pixel inversion (i.e., dot inversion). Therefore, if the threshold voltage for driving liquid crystals is high, such as in a vertical alignment (VA) mode liquid crystal display, the data voltage range used to represent grayscales for displaying images may be significantly reduced if a high threshold voltage is required for driving the liquid crystal. As a result, desired luminance cannot be obtained.
In the case of medium-sized or small-sized display devices such as mobile phones among the liquid crystal displays, row inversion (e.g., where the polarities of the data voltages with respect to the common voltage are inverted in units of a pixel row) may be performed so as to reduce power consumption. However, since the resolution of the medium-sized or small-sized display devices is gradually increasing, the power consumption associated with such devices is also increasing.